Recently, a touch panel, which performs an input function through the touch of an image displayed on a display by an input device, such as a stylus pen or a finger, has been applied to various electronic appliances.
The touch panel may be representatively classified into a resistive touch panel and a capacitive touch panel. In the resistive touch panel, the position of the touch point is detected by detecting the variation of resistance according to the connection between electrodes when pressure is applied to the input device. In the capacitive touch panel, the position of the touch point is detected by detecting the variation of capacitance between electrodes when a finger of the user is touched on the capacitive touch panel. When taking into consideration the convenience of a fabrication scheme and a sensing power, the capacitive touch panel has been spotlighted in a smaller model touch panel recently.
Indium tin oxide (ITO), which has been generally known to those skilled in the art, may be used as a transparent electrode of the touch panel. However, the ITO electrode may have many problems. In the ITO electrode, since an indium material constituting the ITO is rare and vacuum processes, such as sputtering and chemical deposition processes, are essentially required for the ITO coating, the manufacturing process cost are relatively high. In addition, since the ITO electrode is physically easily damaged due to the bending or the curving of a substrate, so that the characteristic of the ITO for the electrode part is deteriorated. Accordingly, the ITO electrode may be not suitable for a flexible device. Further, the ITO electrode represents high resistance and has a limitation in a large size.
In order to solve the problem, researches and studies on an alternative electrode have ben actively carried out. The substitute for ITO is formed by making the shape of the mesh using metallic materials. When the mesh is formed, the mesh may be formed using a nano-pattern and a micro-pattern. For example, a resin layer is formed on the substrate, and imprinted using a mold, so that a pattern may be formed. Thereafter, the electrode layer may be formed on the pattern.
Photocurable resin may be used for a resin layer used in an imprinting process. In general, the photocurable resin is greatly contracted in volume, and has a cross-linking density less than that of other resins. In addition, different resins must be used depending on the types of substrates used when the mold is formed. In addition, the resin must be bonded to the substrate. However, if the substrate is formed of a material difficult in the adhesion to the substrate, the resin layer may be separated from the substrate.
Meanwhile, in the case of the touch window, a moire phenomenon, a black-out phenomenon (a screen is viewed in black at a specific angle) and a rainbow phenomenon (rainbow stains) may occur to exert a malicious influence on visibility.
Meanwhile, recently, the requirement for the flexible touch panel is increased. In other words, if the touch panel is flexible or bendable, the experience of a user will extend. However, indium tin oxide (ITO), which is most widely used material for the transparent electrode of the touch panel, is easy to be physically damaged when the substrate is flexed and bent, so that the electrode property is deteriorated. Therefore, the indium tin oxide (ITO) is not suitable for a flexible device.